Two major integral proteins of the LM cell surface membrane appear to interact with actin, which can be labeled by the lactoperoxidase catalyzed method in broken, but not in intact, cells. We intend to isolate both interacting species (with what appears to be actin covalently bound to its membrane nearest neighbor) in order to characterize the putative actin biochemically by fingerprinting, and to provide material which can be used to establish procedures to purify and characterize biochemically the neighboring integral membrane proteins. Using a new series of reversible asymmetric cross-linkers (alkylimido, azidoaryldisulfides), we will screen for nearest-neighbor protein interactions which cannot be revealed with bis-imidoesters. A general screening will be initiated to describe proteins which have nearest-neighbor interactions with actin in fibroblastic cells and leukocytes. An alkylimido, aziodaryldisulfide will be synthesized highly labeled in the photoactivable portion. Via the site specific imidate it will be reached with a variety of exogenous membrane effectors. These effectors will in turn be incubated with cells as affinity probes to label the receptor for the given effectors. The carbohydrate moiety of glycolipids, isolated by Hakomori's procedures, will be derivatized to the polyhema coated latex beads and used in attempts to identify glycolipid receptors. Attempts will be made to confirm the studies of Roses and Appel indicating differential labeling of red cell ghost proteins upon incubation of control vs. Duchenne subject erythrocyte ghosts with gamma-32P-ATP. If the studies in the latter prove confirmatory, we will extend this study to fibroblastic cell membranes using established cell lines from patient and control subjects. BIBLIOGRAPHIC REFERENCES: Wisnieski, B.J. and Fox, C.F. Correlations between physical state and physiological activities in eukaryotic membranes, especially in response to temperature. In The Molecular Basis of Circadian Rhythms, J.W. Hastings and H.G. Schweiger, eds. Dahlem Konferenzen, Berlin 1975, pp. 247-266 (1976). Takemoto, L.J., Miyakawa, T. and Fox, C.F. Cell surface organization in cultured mammalian fibroblasts. Fed. Proc. 35, 1379 (1976).